The overall goal of this project is to develop a new strategy for manipulating the immune system of a tumor-bearing host to produce an effective tumor-specific response. Murine antibody responses to bovine gamma globulin (BGG) are being used initially as an index of the efficacy of such manipulations. Anti-BGG responses to BGG conjugated with the hapten azobenzene arsonate (ARS) are augmented in certain strains of mice by prior sensitization with the hapten on an unrelated carrier. The gene(s) determining that trait, "hapten help" is/are dominant. The trait is not associated with the major histocompatibility complex (H-2) but with minor histocompatibility loci. Specific objectives of this project will be aimed at answering the following questions. First, can hapten help augment immune responses of cells other than B lymphocytes? Second, can ARS-specific hapten help augment tumor-specific transplantation resistance of a genetically susceptible strain of mouse? Third, if so, what types of immune responses to the tumor are being augmented? Finally, can help by haptens other than ARS be used to augment the differences to other types of neoplasms in other strains of mice?